Innovation is the result of an interactive process. Knowledge-intensive interactions among different partners are associated with a variety of advantages and disadvantages for the actors involved. Therefore, a rich body of literature investigating the impact of R&D collaboration networks on the innovation performance of firms and regions has developed over the last two decades. Those studies come to different results. The aims of this paper are manifold. First, the paper summarizes the results of the relevant literature. Second, a brief overview of the established methods and approaches used in the literature to investigate this research question is given. The third objective is to answer the question whether the achieved results in the literature are predetermined by the employed methods. Finally, relevant gaps for further research are identified. To answer these questions a meta-analysis of the relevant literature is conducted. This study shows that knowledge-intensive interactions have a rather positive impact on the performance of firms and regions. There is also evidence that the employed methods and approaches used in the literature to investigate this research question predetermine the outcome of the research.